| Documentation | Ephrins are peptides that exert their effects via binding to Eph receptors,
which form the largest known family of receptor tyrosine kinases. Ephrins
and their receptors have been implicated in many developmental processes,
including neuronal network formation, the patterning of the neural tube
and the paraxial mesoderm, the guidance of cell migration and vascular
formation. Ephrins have been shown to act as positional labels and play a
key role in axon and neural crest cell pathway finding [1]. Together
with their receptors, they are important regulators of the repulsion and
adhesion of cells involved in cellular organisation.
Interactions between ephrins and their receptors are far from selective,
but can generally be classified as follows: EphA receptors bind glycosyl-
phosphatidylinositol(GPI)-linkage cell membrane anchored ephrin-A ligands,
while EphB receptors bind to ephrin-B proteins that have a transmembrane
and cytoplasmic domain. In addition, ephrin-B proteins can transduce signals
as well as the receptor, resulting in bi-directional signalling. A major
role of ephrins and their receptors is to mediate cell-contact-dependent
repulsion. However, by contrast, ephrins can also trigger an adhesive
response in epithelial cells and are essential for the remodelling of blood
vessels. Recent evidence suggests that the cellular response is dependent
upon the extent of ephrin-receptor binding and that the actin cytoskeleton
is a primary target of the ephrin signal transduction pathway [2].
EPHRIN is a 5-element fingerprint that provides a signature for the ephrins.
The fingerprint was derived from an initial alignment of 6 sequences: the
motifs were drawn from conserved regions spanning the N-terminal half of
the alignment. Two iterations on SPTR37_10f were required to reach
convergence, at which point a true set comprising 28 sequences was
identified.
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